Thermodynamic data are being collected on the oxygen uptake by synthetic oxygen carriers of various cobalt(II) Schiff base and macrocyclic complexes. Similar measurements will be made on Vitamin B12r. Electrochemical studies on the cobalt chelates show that the greater the ease of oxidation (Co(II) yields Co(III) plus e), the better the oxygen uptake ability of the carrier. The resonance Raman spectra of metal oxygen adducts in solution is being studied. The results show changes in O-O and Co-O stretching frequencies for different adducts, which affords information on the nature of the M-O2 bonding in these systems. The photochemical reaction of FeIII-O-FeIII and of FeIII-O2-FeIII will be studied in detail. Appropriate cobalt and iron chelates will be attached to solid polymers or silica gel and the oxygen carrying properties and catalytic properties of such systems will be examined.